400 research outputs found

    Germinação "in vitro" de mogno.

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    bitstream/item/42026/1/BolPesquisa30.pd

    Efeito da escarificação sobre a germinação de sementes de paricá (Schizolobium amazonicum) in vitro.

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    bitstream/item/39906/1/Com-Tec-21-Am-Oriental.pd

    R Coronae Borealis stars in the Galactic Bulge discovered by EROS-2

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    Rare types of variable star may give unique insight into short-lived stages of stellar evolution. The systematic monitoring of millions of stars and advanced light curve analysis techniques of microlensing surveys make them ideal for discovering also such rare variable stars. One example is the R Coronae Borealis (RCB) stars, a rare type of evolved carbon-rich supergiant. We have conducted a systematic search of the EROS-2 database for the Galactic catalogue Bulge and spiral arms to find Galactic RCB stars. The light curves of \sim100 million stars, monitored for 6.7 years (from July 1996 to February 2003), have been analysed to search for the main signature of RCB stars, large and rapid drops in luminosity. Follow-up spectroscopy has been used to confirm the photometric candidates. We have discovered 14 new RCB stars, all in the direction of the Galactic Bulge, bringing the total number of confirmed Galactic RCB stars to about 51. After reddening correction, the colours and absolute magnitudes of at least 9 of the stars are similar to those of Magellanic RCB stars. This suggests that these stars are in fact located in the Galactic Bulge, making them the first RCB stars discovered in the Bulge. The localisation of the 5 remaining RCBs is more uncertain: 4 are either located behind the Bulge at an estimated maximum distance of 14 kpc or have an unusual thick circumstellar shell; the other is a DY Per RCB which may be located in the Bulge, even if it is fainter than the known Magellanic DY Per. From the small scale height found using the 9 new Bulge RCBs, 61<hBulgeRCB<24661<h^{RCB}_{Bulge}<246 pc (95% C.L.), we conclude that the RCB stars follow a disk-like distribution inside the Bulge.Comment: 20 pages, 26 figures, Accepted in A&

    Differences in genotype and virulence among four multidrug-resistant <i>Streptococcus pneumoniae</i> isolates belonging to the PMEN1 clone

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    We report on the comparative genomics and characterization of the virulence phenotypes of four &lt;i&gt;S. pneumoniae&lt;/i&gt; strains that belong to the multidrug resistant clone PMEN1 (Spain&lt;sup&gt;23F&lt;/sup&gt; ST81). Strains SV35-T23 and SV36-T3 were recovered in 1996 from the nasopharynx of patients at an AIDS hospice in New York. Strain SV36-T3 expressed capsule type 3 which is unusual for this clone and represents the product of an in vivo capsular switch event. A third PMEN1 isolate - PN4595-T23 - was recovered in 1996 from the nasopharynx of a child attending day care in Portugal, and a fourth strain - ATCC700669 - was originally isolated from a patient with pneumococcal disease in Spain in 1984. We compared the genomes among four PMEN1 strains and 47 previously sequenced pneumococcal isolates for gene possession differences and allelic variations within core genes. In contrast to the 47 strains - representing a variety of clonal types - the four PMEN1 strains grouped closely together, demonstrating high genomic conservation within this lineage relative to the rest of the species. In the four PMEN1 strains allelic and gene possession differences were clustered into 18 genomic regions including the capsule, the blp bacteriocins, erythromycin resistance, the MM1-2008 prophage and multiple cell wall anchored proteins. In spite of their genomic similarity, the high resolution chinchilla model was able to detect variations in virulence properties of the PMEN1 strains highlighting how small genic or allelic variation can lead to significant changes in pathogenicity and making this set of strains ideal for the identification of novel virulence determinant

    Brazilian coral reefs in a period of global change: A synthesis

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    Abstract Brazilian coral reefs form structures significantly different from the well-known reef models, as follows: (i) they have a growth form of mushroom-shaped coral pinnacles called "chapeirões", (ii) they are built by a low diversity coral fauna rich in endemic species, most of them relic forms dating back to the Tertiary, and (iii) the nearshore bank reefs are surrounded by siliciclastic sediments. The reefs are distributed in the following four major sectors along the Brazilian coast: the northern, the northeastern and the eastern regions, and the oceanic islands, but certain isolated coral species can be found in warmer waters in embayments of the southern region. There are different types of bank reefs, fringing reefs, isolated "chapeirões" and an atoll present along the Brazilian coast. Corals, milleporids and coralline algae build the rigid frame of the reefs. The areas in which the major coral reefs occur correspond to regions in which nearby urban centers are experiencing accelerated growth, and tourism development is rapidly increasing. The major human effects on the reef ecosystem are mostly associated with the increased sedimentation due to the removal of the Atlantic rainforest and the discharge of industrial and urban effluents. The effects of the warming of oceanic waters that had previously affected several reef areas with high intensity coral bleaching had not shown, by the time of the 2010 event, any episodes of mass coral mortality on Brazilian reefs

    Comparison of prestellar core elongations and large-scale molecular cloud structures in the Lupus 1 region

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    Turbulence and magnetic fields are expected to be important for regulating molecular cloud formation and evolution. However, their effects on sub-parsec to 100 parsec scales, leading to the formation of starless cores, are not well understood. We investigate the prestellar core structure morphologies obtained from analysis of the Herschel-SPIRE 350 mum maps of the Lupus I cloud. This distribution is first compared on a statistical basis to the large-scale shape of the main filament. We find the distribution of the elongation position angle of the cores to be consistent with a random distribution, which means no specific orientation of the morphology of the cores is observed with respect to the mean orientation of the large-scale filament in Lupus I, nor relative to a large-scale bent filament model. This distribution is also compared to the mean orientation of the large-scale magnetic fields probed at 350 mum with the Balloon-borne Large Aperture Telescope for Polarimetry during its 2010 campaign. Here again we do not find any correlation between the core morphology distribution and the average orientation of the magnetic fields on parsec scales. Our main conclusion is that the local filament dynamics---including secondary filaments that often run orthogonally to the primary filament---and possibly small-scale variations in the local magnetic field direction, could be the dominant factors for explaining the final orientation of each core

    Caracterização físico-química e de compostos funcionais em frutos de pitaya.

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    A pitaya é uma fruta rústica, pertencente à família Cactaceae, sendo conhecida mundialmente como "Fruta-do-Dragão?. De acordo com a espécie, seus frutos podem apresentar características diversificadas, como formato, presença de espinhos, cor da casca e da polpa, refletindo em alta variabilidade genética (JUNQUEIRA et al., 2007). No Brasil é comum serem encontradas, em estágio nativo no Cerrado e Caatinga, espécies do gênero Selenicereus e Hylocereus, dentre elas a Selenicereus setaceus, popularmente conhecida como pitaya-do-cerrado (JUNQUEIRA et al., 2002). Atualmente, as espécies de pitaya mais cultivadas no mundo são a pitaya de casca vermelha (Hylocereus undatus (Haw.) Britton e Rose) e a de casca amarela (Selenicereus megalanthus (K. Schum ex Vaupel) (MIZRAHI et al., 1997; NERD et al., 2002). Devido ao seu sabor doce e suave, de polpa firme e repleta de sementes e aliado às suas propriedades nutricionais e funcionais, faz da pitaya um produto de grande aceitação nos mercados consumidores, o que têm despertado o interesse nos produtores. O alto valor pago pelo quilo da fruta, que pode variar de dez a sessenta reais, dependendo da época do ano e da demanda, também constitui um grande atrativo para o plantio dessa frutífera (JUNQUEIRA et al., 2002; SOUZA, 2010). Devido à escassez de estudos sobre a pitaya, torna-se fundamental a ampliação do conhecimento acerca dessa espécie, viabilizando a produção de mudas e fornecendo subsídios para a seleção de materiais promissores. Neste trabalho, objetivou-se realizar a caracterização físico-química e de compostos funcionais nas espécies de pitaya Hylocereus costaricencis e Hylocereus undatus
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